Chapter nine deals with contracts which require writing. And these are slightly unusual really, most contracts can be concluded entirely orally,without anything ever being put into writing. And those contracts might be of huge value and great importance. But in some situations, clearly you do need to satisfy certain formalities. And, I think it's most important here to distinguish between contracts which are void without such formalities, and therefore have no effect, and contracts which are not void but unenforceable. So, they might still have some legal effects, unlike void contracts, but if a contract is unenforceable a party won't be able to sue on it unless, and until appropriate written evidence can be produced. And principally we're thinking about contracts of guarantee. Which are unenforceable, if not evidenced in writing. Whereas contracts for the sale of land, or disposition of an interest in land, are void if not made in writing. But at the moment there's quite a lot of debates about what you need for signature, especially because sadly we're in the middle of a pandemic where people cannot easily be physically present to have awet signature on paper. And because I've made clear that what we're really looking for is an intent to authenticate the document in question. So, an intent to authenticate the contract. And one very recent case has said that even an automatic email footer can mean that the requirement for signature is fulfilled, which I think is perhaps one example of how flexible contract law can be in adapting to changing circumstances. And in particular, the changing expectations of commercial parties. So, I think it's increasingly recognized that contracts shouldn't be deprived of legal effectiveness, just because they're made by electronic means. And the law here has adapted to advances in technology.